Nice Cacti Install How To

RedHat / CentOS Install and Configure Cacti Network Graphing Tool

Reset file permissions of RPM packages

A disastrous mistake anyone can make on their Linux server is to chown or chmod their entire filesystem.

You can reset the permissions of packages installed with rpm.

To reset file permissions:

To reset ownership permissions:

One-Liners

Search for multiple processes in one command. Example in using multiple variables.

Lower the reserved disk space to 0%. By default Linux will reserve 5% of each file system as reserve free disk space.

Compare two files on two remote file systems. I saw this on Command-line-fu.

RPM Database Corruption

So I recently came across a situation where rpm would just hang or give out transaction errors. It turns out that the database cache files became corrupt. Here is an example of one of the errors:

warning: waiting for transaction lock on /var/lock/rpm/transaction

# cd /var/lib/rpm

Look for the files that start with double underscores “__”. These are the cache files, and you will want to delete all of them.

# rpm __*

# rpm –rebuilddb